A visit to Mike's Decals' "donor kit" listing on his website may be productive. They're usually bagged without instructions or Decals for decent prices.
I have 2 rear bench seats; 1 from the Revell 69 Nova and 1 from the old AMT Nova. If you want them, PM me your address and I'll get them into the mail to you. I don't need anything for them, just glad I can help!
The resin Corvair modified body, formally produced by Big Donkey Resins, is now produced by Powerslide and available through Mike's Decals. It's product #013 '61 Corvair or #014 '66 Corvair. Both are $25 a piece, with hood
I just did a Google search for 1936 Packard 12, there were numerous sites. I chose the one for Volo Museum and dozens of photos came up, including the imterior
I have one, PM me your address and it's yours. I'm combining the chassis/interior/drivetrain with a resin King Cobra body; so if you wants any other body parts, let me know and they're yours